In modern machines and vehicle transmissions it is nowadays sought to fill these with engine oil and transmission oil once during their lifetime, and the life of such a transmission being, for example, typically on the order of 1 million kilometers.
The machine or transmission oil serves to lubricate and cool all the mechanical elements. Since it is never changed, it is exceptionally suitable for machine or transmission diagnosis since, over the course of time, all kinds of abrasion particles accumulate in the oil. Consequently, analysis of the machine or transmission oil provides information about the condition of the machine or transmission.
In this, ferritic wear is of particularly great importance since in almost any type of incipient damage, such as roller bearing wear, the formation of pitting in the gear teeth leading to tooth fracture, wear of the gear cage bolts, etc., ferritic wear alone, or in combination with other types of wear (non-ferrous metal wear, molybdenum degeneration, etc.), occurs.
In the state of the prior art, there now exists an oil diagnosis system disclosed by the present applicant in WO 02/46744, which detects ferritic wear metals by means of a wear sensor based on the Hall effect. This measurement system is in an oil duct of a transmission or a machine. It is designed as a sensor in a two-part sensor housing. A Hall sensor is arranged in the upper part of the sensor housing. The Hall sensor detects the ferritic wear particles which accumulate on the capturing magnet in the lower part of the sensor housing.
Such oil diagnosis systems are undergoing continual further development because, for example, the assembly of the two-part housing in the oil duct is relatively difficult to carry out. Further development potential is available in the design of the sensor's electrical supply. For example, it is extremely important to keep the supply voltage of the Hall sensor stable so that there will be no fault-inducing fluctuations in the measurement signal.
Accordingly, the purpose of the present invention, starting from the prior art mentioned above, is to provide a method for machine diagnosis, and especially for transmission diagnosis, which selectively detects ferrous wear and which enables on-line diagnosis indicating the condition of the machine or transmission. In addition, a device for implementing the method should be indicated.